The present invention relates to an apparatus for producing stator cores or stator coils of electric machines such as generators or motors and, more particularly, to an apparatus for automatically producing stator cores or coils by continuously plastic working a strip metal in a substantially spiral form.
Conventionally, stator cores or stator coils (Hereinafter, only the stator core will be referred to representatively, and the stator coil will be neglected in the description, for the purpose of clarity.) have been fabricated by laminating a plurality of annular strip metals punched out from a sheet blank, or by first winding a strip metal around a core metal to form multiple layers, then cutting the coiled strip metal into a number of annular strip metals and finally laminating thus obtained annular strip metals in such a manner that the cut portions are not superimposed.
However, the first mentioned method employing the punching process is disadvantageous in that considerable part of the sheet blank is inevitably wasted. The second method has been found also to be unsatisfactory, although it can afford an enhanced yield as compared with the first method due to the fact that the outer portion of the annular strip metal is subjected to a tensile force, while the inner portion is compressed, so that wrinkles or corrugation are produced at the radially inner portion. These wrinkles irregularly increase the thickness of the annular strip metal and can be corrected through troublesome efforts employing a press. In addition, both of the conventional measures described above require manual labor, thus presenting inefficiency.
In order to eliminate these disadvantages, a variety of machines or apparatus have been proposed for subjecting a strip metal to plastic working while applying a predetermined lateral pressure on and constraining the strip metal at the outer edge thereof. However, these apparatus are unacceptably large in size and complicated in construction, and provide unsatisfactory accuracy in thickness of the strip metal which has been subjected to plastic working.